1. Field of the Invention
The present invention relates to a device and method for opening and closing a barrier in a zoom camera. More particularly, the present invention relates to a device and method for opening and closing a barrier in a zoom camera in which opening and closing of the barrier is performed by a focus control motor mounted in a shutter block such that problems arising in the use of a zoom motor are avoided.
2. Description of the Related Art
Generally, zoom cameras are equipped with a focus system in which the focal length is changed by multiple steps. Zoom cameras typically also include a zoom system. These two systems operate separately in most zoom cameras. That is, the zoom system begins to operate when a power switch is turned on and the focus system begins to operate when a shutter is operated.
A zoom camera comprising the above zoom system and focus system has a barrier installed in a front panel to protect the lens. The barrier is linked with the zoom system to be opened or shut respectively as a power switch is turned on and off.
FIG. 12 shows a partial cross-sectional view of a lens system in the conventional zoom camera. With regard to a structure in the conventional lens system used to open and close the barrier, formed on a circumference of a movable lens barrel 201 and assembled to a fixed lens barrel 203 are gears connected through a gear train 207 to a zoom motor 205 and to a helicoid pattern meshed to a helicoid pattern formed on an inner circumference of the fixed lens barrel 203. The fixed lens barrel 203 is fixed to a body of a camera (not shown). The rotational force of zoom motor 205 is transmitted through the gear train 207 to the movable lens barrel 201.
With the above structure, the opening and closing of barrier sectors 213 are achieved by (a) transmitting the rotational force of the zoom motor 205 to the movable lens barrel 201; (b) rotational and rectilinear movement of the movable lens barrel 201 with respect to the fixed lens barrel 203, whereby the revolving power is conveyed; and (c) using the rotational force of the movable lens barrel 201 to open and close the barrier sector 213.
That is, the structure used to open and close the barrier in the conventional zoom camera is such that a barrier driving lever 209 is disposed to receive the rotational force of the movable lens barrel 201, and by the connection of a ring portion 211 of the barrier driving lever 209 to the barrier sectors 213, the barrier sectors 213 are opened or closed according to the rotation of the ring portion 211. The barrier sectors 213, which are designed to open or close according to the rotation of the ring portion 211, are hinged with the ring portion 211 through a driving pin 229 and are disposed in a front panel such that they (the barrier sectors 213) can freely rotate.
Focusing is carried out by the forward and backward movement of a focus lens group 217 inside the above movable lens barrel 201. The focus lens group 217 is disposed in a shutter block 219, and a focusing motor 221 is provided in the vicinity of the focus lens group 217 and within the shutter block 219. To focus, a gear train 237 is connected to the focusing motor 221 and a focusing ring 223 is rotatably meshed with the gear train 227. Further, a connection lever 225 is connected to the focusing ring 223, and is fixedly connected to the focus lens group 217.
When the power switch of a zoom camera having the above structure is turned on, the zoom motor 205 begins to operate, and the driving power of the zoom motor 205 is transmitted through the gear train 207 such that the movable lens barrel 201 is moved to a wide position. During this process, the barrier driving lever 209 is rotated, thereby rotating the pair of the barrier sectors 213 to open the same.
When the shutter switch is operated in a state where the barrier sectors 213 are open, the focusing motor 221 starts running, and the rotational power of the focusing motor 221 conveyed through the gear train 227 rotates the focusing ring 223. The focusing ring 223, by moving the connection lever 225 connected to the focus lens group 217, moves the focus lens group 217 to a predetermined position and then returns to its initial position. When the power switch of the zoom camera is turned off, the movable lens barrel 201 returns to its initial position, and the movable lens barrel 201 is disconnected from the barrier driving lever 9 to close the barrier sectors 213.
In the above structure used to open and close the barrier of the conventional zoom camera, since a plurality of structural elements are integrated with the movable lens barrel 201, great stress is put upon the zoom motor 205. That is, in the case where the barrier sectors 213 are opened or closed simultaneously while zooming is performed, driving all of the necessary elements places a significant strain on the zoom motor 205.
Further, it is possible that the opening and closing of the barrier sectors 213 will not be smooth as a result of assembly errors and/or incorrect adjustments related to focusing made in the movable lens barrel 201.
In addition, the lens may become damaged by foreign substances or an external impact because the barrier sectors 213 are left opened during the entire zooming operation. Therefore, if the barrier sectors 213 are closed by operation of the power switch to prevent damage to the lens, the process of turning the power switch back on, opening the barrier sector 213, and finally performing zooming is inconvenient.
Finally, since the power switch is turned off to close the barrier sectors 213, the taking of photos or other such quick shots is not possible even with the operation of a release switch, and the user must go through the cumbersome step of first turning the power switch on to open the barrier sectors 213 even before focusing and zooming can be performed.